1. Field of the Invention
The present invention relates to a method of manufacturing a liquid discharge head which discharges a liquid, and a liquid discharge head, more particularly to an ink jet recording head which discharges ink to perform recording, and a method of manufacturing the ink jet recording head.
2. Related Background Art
As an ink jet recording head which discharges ink to perform recording, there is known a constitution (“side shooter type recording head”) in which an ink droplet is discharged in a direction vertical to a substrate on which there is formed an ink discharge energy generating element such as a heat generating resistor.
The following method is known as a method of manufacturing such side shooter type recording head.
In U.S. Pat. No. 5,478,606, there is disclosed a method of manufacturing an ink jet recording head, including the following steps. First, an ink flow path pattern is formed of a soluble resin on the substrate on which the ink discharge energy generating element is formed. Subsequently, a coating resin containing a solid epoxy resin is dissolved in a solvent at ordinary temperature, and a soluble resin layer is coated with a solvent to thereby form the coating resin layer constituting an ink flow path wall on the soluble resin layer. Moreover, an ink discharge port is formed in the coating resin layer above an ink discharge pressure generating element to elute the soluble resin layer.
Moreover, in U.S. Pat. No. 5,331,344, there is disclosed a method of manufacturing an ink jet recording head, including the following steps. First, a first photosensitive material layer for forming an ink oath is disposed on the substrate on which the ink discharge energy generating element is formed to subject the first photosensitive material layer to pattern exposure for forming the ink path. Subsequently, a second photosensitive material layer is further disposed on the first photosensitive material layer to subject the second photosensitive material layer to exposure of a pattern for forming the ink discharge port and an ink supply port. Thereafter, the first and second photosensitive material layers are developed.
On the other hand, in U.S. Pat. No. 5,278,584, there is disclosed a method of manufacturing an ink jet recording head, in which an orifice plate member is laminated on a member integrated with the substrate provided with the ink discharge energy generating element and constituting an ink flow path wall. The orifice plate member is constituted of a flexible circuit substrate material, and a thermosetting adhesive or the like is used in laminating the orifice plate member on the ink flow path wall.
However, the above-described ink jet recording heads have the following problems, respectively.
That is, in the method disclosed in U.S. Pat. No. 5,478,606, since the substrate on which the ink flow path pattern is formed is coated with the solvent to form the coating resin layer constituting the ink flow path wall, the coating resin layer extends along the ink flow path pattern. Therefore, in the ink jet recording head manufactured by this method, fluctuations are generated in a thickness of an orifice plate to form thick and thin portions, and there might occur a problem in a reliability of the thin portion of the orifice plate depending on use conditions.
In the method disclosed in U.S. Pat. No. 5,331,344, the above-described fluctuations of the film thickness are not generated, but there is a possibility that a mutually dissolved layer of the respective materials is generated in a boundary surface between a latent image pattern upper layer portion of the first photosensitive material layer and the second photosensitive material layer. Since this mutually dissolved layer remains even after the development of the first and second photosensitive material layers, a discharge control itself of the ink jet recording head might be adversely influenced.
On the other hand, in the method disclosed in U.S. Pat. No. 5,278,584, the above-described problems due to the film thickness fluctuations and the mutually dissolved layer are not generated. However, since the orifice plate member provided with the ink discharge port is laminated on the member constituting the ink flow path wall, there is a possibility that a problem is generated in a precision in positioning the members. In a case where a deviation is generated, a discharge direction of the ink droplet deviates from a desired direction, and it accordingly becomes difficult to perform high-precision printing/recording. In recent years, it has been demanded that in the ink jet-recording head, a discharge amount be reduced in order to realize a picture quality, and an arrangement density of the discharge ports be increased, but it is difficult to satisfy such requirement by the method disclosed in U.S. Pat. No. 5,278,584.